Keratinocytes have a well developed system for the processing of xeniobiotics and other external pollutants.
The primary detoxification mechanisms are based on the Phase I and Phase II enzymes.
Phase I enzymes such as the cytochrome P450 family oxidize or reduce the xenobiotic. Phase II enzymes such as glutathione-s-transferase conjugate the foreign chemicals with other polar compounds, prior to excretion.
These enzymes are evaluated with and without active ingredient treatment by ELISA.